CVE-2024-49963 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
mailbox: bcm2835: Fix timeout during suspend mode
During noirq suspend phase the Raspberry Pi power driver suffer of firmware property timeouts. The reason is that the IRQ of the underlying BCM2835 mailbox is disabled and rpi_firmware_property_list() will always run into a timeout [1].
Since the VideoCore side isn't consider as a wakeup source, set the IRQF_NO_SUSPEND flag for the mailbox IRQ in order to keep it enabled during suspend-resume cycle.
[1]
PM: late suspend of devices complete after 1.754 msecs WARNING: CPU: 0 PID: 438 at drivers/firmware/raspberrypi.c:128 rpi_firmware_property_list+0x204/0x22c Firmware transaction 0x00028001 timeout Modules linked in: CPU: 0 PID: 438 Comm: bash Tainted: G C 6.9.3-dirty #17 Hardware name: BCM2835 Call trace: unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x34/0x44 dump_stack_lvl from __warn+0x88/0xec __warn from warn_slowpath_fmt+0x7c/0xb0 warn_slowpath_fmt from rpi_firmware_property_list+0x204/0x22c rpi_firmware_property_list from rpi_firmware_property+0x68/0x8c rpi_firmware_property from rpi_firmware_set_power+0x54/0xc0 rpi_firmware_set_power from _genpd_power_off+0xe4/0x148 _genpd_power_off from genpd_sync_power_off+0x7c/0x11c genpd_sync_power_off from genpd_finish_suspend+0xcc/0xe0 genpd_finish_suspend from dpm_run_callback+0x78/0xd0 dpm_run_callback from device_suspend_noirq+0xc0/0x238 device_suspend_noirq from dpm_suspend_noirq+0xb0/0x168 dpm_suspend_noirq from suspend_devices_and_enter+0x1b8/0x5ac suspend_devices_and_enter from pm_suspend+0x254/0x2e4 pm_suspend from state_store+0xa8/0xd4 state_store from kernfs_fop_write_iter+0x154/0x1a0 kernfs_fop_write_iter from vfs_write+0x12c/0x184 vfs_write from ksys_write+0x78/0xc0 ksys_write from ret_fast_syscall+0x0/0x54 Exception stack(0xcc93dfa8 to 0xcc93dff0) [...]
PM: noirq suspend of devices complete after 3095.584 msecs
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Analysis
by VulDB Data Team • 03/21/2026
The vulnerability CVE-2024-49963 affects the Linux kernel's handling of mailbox communication during system suspend operations on Raspberry Pi devices. This issue specifically targets the bcm2835 mailbox driver implementation which is responsible for communication between the ARM processor and the VideoCore GPU firmware on Raspberry Pi platforms. During the noirq suspend phase, the system attempts to manage power states for various devices including the Raspberry Pi power driver, but encounters firmware property timeouts that prevent proper system suspend functionality. The root cause stems from the mailbox interrupt being disabled during suspend cycles, which breaks the expected communication flow between the host system and firmware components.
The technical flaw manifests when the rpi_firmware_property_list() function attempts to communicate with the VideoCore firmware but consistently times out due to the disabled mailbox IRQ. This timeout occurs because the system's power management subsystem disables interrupts during the suspend phase to prevent spurious wakeups, but fails to account for the specific requirements of firmware communication during these critical phases. The interrupt handling mechanism in the bcm2835 mailbox driver does not properly preserve interrupt functionality needed for firmware property transactions during suspend-resume cycles, leading to a complete failure of the suspend operation.
This vulnerability impacts the operational reliability of Raspberry Pi systems by preventing proper system suspend functionality, which can lead to increased power consumption and potential system instability during power management operations. The timeout condition causes the system to log warnings and potentially fail to complete suspend sequences properly, affecting both battery-powered devices and systems requiring reliable power state transitions. The issue particularly affects systems using the Raspberry Pi power management framework where the VideoCore firmware component is essential for proper system operation and device power state management.
The mitigation strategy involves setting the IRQF_NO_SUSPEND flag for the mailbox IRQ in the bcm2835 mailbox driver implementation. This flag ensures that the interrupt remains enabled during the suspend-resume cycle, allowing firmware communication to proceed normally even when other interrupts are disabled. This approach aligns with the established principles of interrupt handling during system power management phases and follows the patterns defined in the Linux kernel's power management subsystem design. The fix addresses the fundamental mismatch between the interrupt handling requirements of firmware communication and the power management constraints applied during suspend operations.
This vulnerability demonstrates the complexity of managing interrupt states during system power transitions and highlights the importance of considering firmware communication requirements in power management design. The issue relates to CWE-362 which deals with concurrent execution using lock objects and the broader category of improper handling of interrupt contexts during system transitions. The ATT&CK framework would classify this under privilege escalation through system firmware manipulation and system service management, as the vulnerability affects the kernel's ability to properly manage system power states and firmware interactions during critical operations. The fix ensures proper interrupt preservation during suspend cycles while maintaining system security and power management integrity.